For as long as I can remember, my son has always called a tomato a "potato". With confidence. So, sometime back, I gave up correcting that it is a tomato, and played along calling it a potato. As a parent, you get the instinct when your child is doing it on purpose.

For lunch everyday, LG has a boiled tomato sprinkled with salt. This afternoon, I asked him what he was having? He replied, "Tho-maa-to." I grinned and asked him, "Are you sure this is not a Paa-tho-to?" And LG replied, "Tho-maa-to." This, for me, is as huge a milestone as was his turning over, or crawling, or walking, or talking.